The CPU (Central Processing Unit), is the chip in the computer that actually performs the operations and calculations that are done as a program runs. It is essentially what executes a program.

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How to compare usage of memory by Window Managers?

I'd like to test a few window managers to see which of them takes less memory and CPU in certain time period (so is better choice for older computers). I'd like to make the tests myself (not to read a ...
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1answer
48 views

What is the difference between opening an application from terminal Vs directly opening it?

I could open Firefox browser either by clicking FF icon on desktop or by running ~/firefox/firefox & in the terminal. What are the differences in these two ways of running? I am wondering because ...
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1answer
2k views

Should I install the AMD/Intel microcode packages when running Debian?

Should I install the AMD/Intel microcode packages when running Debian? What exactly do they do, and when should/shouldn't I install them? Why are they in non-free?
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1answer
5k views

Total CPU usage and CPU usage under processes list is different in FreeBSD top implementation?

For some reason, overall CPU usage on my FreeBSD machine fluctuates between 1% and 85%, but the CPU usage in processes column never adds up to this amount. For example here the overall CPU usage is 83....
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1answer
152 views

Minimizing hardware interrupts

I am using a modified Linux kernel as a soft real-time OS, on a system that has an architecture like this: CPU1 and CPU2 have 8 cores each. I have 4 processes that need to be run with minimum ...
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2answers
878 views

Number of cores on FreeBSD

What would the equivalent of Debian's nproc be in FreeBSD? I'm trying to include this in a bash script variable so if it could just print out the number of cores that would be fantastic.
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1answer
285 views

Why PowerVM LPAR CPU utilization is negative

For a specific case I compute an PowerVM LPAR CPU utilization to be a large number less than zero. I am fetching the lpar sample event using: lslparutil -r lpar -m P750 --filter "lpar_names=i5lp5" -...
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1answer
100 views

CentOS vmtoolsd usage 100%

I am new to CentOS and VirtualBox. I installed CentOS 7 on VirtualBox but see the CPU usage at 100% by vmtoolsd. I tried multiple ways to bring it down e.g. by doing "lodctr /R" and removing open-...
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2answers
31 views

What tools can I use to diagnose the exact reason for laptop slowness? And how do I use those tools?

I am running Linux Mint 17 on my laptop. When using applications (mainly Web Browsers) the machine freezes for little time periods. The CPU indicates 100% usage at such times, but this only seems to ...
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1answer
78 views

Set CPU affinity for the specific program?

How can I set CPU affinity for the specific program (say gzip) to always run on specific core or cores (core 1, for example)? I read about taskset, but can it be used before program is actually used ...
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2answers
154 views

Why is the range of load average not 0-1+ for all cpu's together?

I know that load average is 0-1(or 0-1024) per cpu. E.g a busy quad-core can have a load average of 4.0 or higher. (e.g if there are many tasks). I understand it can be huge like 100+ etc. I also ...
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1answer
369 views

How can I find the CPU resource utilization of a process and all its children [duplicate]

If I have a process that spawns child processes, is there a good way to get a single number representing the combined CPU use of that process and its children? i.e is there a simple shell command ...
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2k views

High Idle CPU / Low CPU Load average

After removing APC (alternative php cache), I noticed that there are less pagination access and less dirty pages but in the same time: High idle CPU Very low CPU load (relatively to the time before ...
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1answer
483 views

Determine the intel CPU family for C compiler?

I am checking the CPU information on a Linux server, and tuning options of the Intel C compiler icc for my C code running on the server's specific architecture. I am thinking about choosing the value ...
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2answers
374 views

Monitor single process to logfile perodicly

Based on this question, I would like to log the performance of a specific process, with a frequency of say one second, to a csv (comma separated value) log file. Something like: timestamp(unix),...
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2answers
3k views

Hyperthreading not detected by Linux [closed]

I have a Dell server with two Intel Xeon E5645 cpus, each cpu has 6 cores, and each core is hyperthreaded (i.e. should be equivalent to two virtual cores). I installed CentOS 6.2 on this server and it ...
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0answers
35 views

Suspend system instead of shutdown on CPU overheat

I have Linux Mint. The system Linux Mint is installed on, shuts down immediately on overheating. Is there anyway the system doesn't shutdown, but goes to standby state? The machine can always be ...
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0answers
28 views

Assign virtual core number to specific real core

Is there any way to assign ''linux core numbers'' to specific real cores? I'm working with an asymmetric architecture, so not all cores are the same, and I want to assign specific cores number to ...
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0answers
363 views

CPU Pipe Underrun Errors

Every time upon booting and then unlocking my GUI session on Kali Linux 2.0, I get another of this error in Virtual Console 1: [ 1235.586792] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR*...
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1answer
62 views

how to get processor that thread is currently assigned to?

I've found such column in ps -elF: PSR processor that process is currently assigned to. I need something similar but for threads. ps huH p 1234 prints threads of process 1234, can I somehow add "...
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0answers
59 views

What does the “k” metric mean in the “sa” output?

From man sa: k cpu-time averaged core usage, in 1k units My questions: How is it calculated? What is the significance?
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0answers
176 views

Help troubleshoot a very slow system performance (Kubuntu, intel graphics) [closed]

As the title says the performance of my laptop is simply terrible. i3 M380 @ 2.53GHz, 4GB RAM (of which more than 2GB is rarely used), intel HD graphics (to external monitor through HDMI). It takes ...
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672 views

Disable CPU scaling with U 1404

I know there are a lot of things about this topic but I couldn't find anything not older than 4 years. As the stuff develops so fast I hope it is fine to ask again a few years later. What is ...
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0answers
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Intel Xeon stuck at 800mhz CPU Freq on RHEL 6.5 [duplicate]

Currently running into a headache trying to figure out why my CPU speed is stuck as such a low frequency. After doing some research, I found that cpuspeedutil does actually control the state of the ...
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0answers
159 views

Limit CPU cycles inside of Xen

I'd like to run some minimum-expectation benchmarks on EC2, but I'm having an issue of high variability in my output data. Specifically, they keep giving me more CPU than I'm minimally entitled to, ...
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279 views

Unable to reduce core frequency freebsd

I'm working on a FreeBSD project where I need to maintain the temperature of the processor below a threshold value. In order to reduce the temperature I'm trying to dynamically change the frequency of ...
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2answers
1k views

Why I can not use all the 100% potential of CPU?

I am using my computer clusters to run a MD C program but I can not use full potential of those clusters. But the this node have 16 CPUs and I also only give 15 jobs for those CPUs. But I can not ...
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5answers
3k views

How to find which machines are idle on a cluster of many nodes

I run measurements on a cluster consisting of 32 nodes/machines. I do not require all nodes, only 4, for example. The problem is most of the time, the nodes are busy with other people running their ...
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2answers
203 views

Should I care for applications that increase the system Load in order to prevent overheating?

I found that my "PCI Adapter" overheats when load is above 4.0 (having 4 cores). It does NOT overheat when the load is below 4.0 (but I had an overclocked memory that was causing trouble as I explain ...
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2answers
698 views

Are “kernel mode” and “user mode” hardware features or software features?

I read that there are two modes called “kernel mode” and “user mode” to handle execution of processes. (Understanding the Linux Kernel, 3rd Edition.) Is that a hardware switch (kernel/user) that is ...
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3answers
3k views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...
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3answers
235 views

CPU or RAM better in old machine?

I'm planning to use one of two old computers as a low-volume backup server. The machine will be online and files will be backed up over ssh/rsync. I will do a minimal install of Ubuntu or Debian ...
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2k views

Kondemand process consumes most of my CPU

Following is the output from top: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3551 mysql 20 0 10.0g 84m 4052 S 9.4 0.1 544:39.87 mysqld 2311 root 20 0 0 ...
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2answers
158 views

Linux and CPU usage

What does it mean for a core to run at different loads in different moments? How does a 10% load differ from a 90% load? How is this number calculated, essentially?
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2answers
14k views

Top “id” is using 50-99% of CPU

My i386 Lubuntu install is running with a constantly 100% CPU. Using top I have diagnosed "%id" as using up a lot of CPU, usually between about 50% and 99%. Why is this happening, and how can I stop ...
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3answers
2k views

How can I start a process using cpulimit?

I am trying to use cpulimit for testing an app I'm developing under low resource conditions, and I need the process to start under the influence of cpulimit. It is not sufficient to start the program ...
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2answers
106 views

what means 'processor execution level'?

I'm reading about Unix in a book "The design of UNIX operating system". But, in the text middle of process state (e.g wakeup, interrupt), there is term 'raise processor execution level'. What does "...
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3answers
91 views

Type and the speed of CPU using the lscpu command

I want to determine the type and speed of my CPU so I executed the CPU command, However, I have some confusion, so from my output I can't really determine what is my CPU type and my speed is 1600 MHZ, ...
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2answers
108 views

Optimal BIOS CPU power config for performant Hadoop?

I'm in the process of setting up a Hadoop cluster and have so far been unable to find a good answer for how to configure CPU power in the BIOS for Linux. My BIOS give a variety of options with ...
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1answer
97 views

Threads vs interrupts

What does it mean when threads are time-sliced? Does that mean they work as interrupts, don't exit while routine is not finished? Or it executes one instruction from one thread then one instruction ...
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1answer
843 views

AIX CPU usage - how to know how many CPUs running?

Over AIX 6.1 - I do see the following output, it says I have 16 Max Physical CPUs; but there are only 8 active - why is that? The system will use the remaining 8 if needed? Or are they disabled? # ...
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4answers
2k views

Run linux process at very very low priority?

I have regular process that not so important but will consume so much CPU power, and I have another process which is really important, but it spend most of the time idle, but when it got a job it ...
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1answer
413 views

why is my laptop-mode configuration being ignored?

I am running Debian GNU/Linux Jessie (testing) on my laptop. I enabled the systemd laptop-mode service: $ sudo laptop_mode Laptop mode enabled, active [unchanged] and in my /etc/laptop-mode/conf.d/...
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2answers
2k views

Kernel not detecting multicore cpu

Kernel Version 3.3.4-5.fc17.x86_64 CPU info: sashan@dhcp-au-122 ~ $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) ...
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1answer
1k views

Which “Processor family” to choose under “Processor type and features”?

I have recently compiled a minimal kernel for my Intel(R) Pentium(R) Dual CPU T3400 @ 2.16GHz, and chose CONFIG_MCORE2 (Core 2/newer Xeon) under "Processor type and features > Processor family" I ...
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38 views

What is the meaning of Tasks and Running in htop screen?

On my computer it shows Tasks 314; 24 running What do these numbers mean? Is 1 Task = 1 process? Why isn't the number of running tasks = number of CPUs then? (I have more than 24 CPUs) edit. ...
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1answer
55 views

Why is 64bit Ubuntu running Slower? [closed]

I have 2 mostly identical machines, and Acer and a Lenovo, both with Intel Atom 230 CPU @ 1.60GHz and 1GB of DDR2 RAM. The acer has a fresh install of 64Bit Ubuntu 14.04 LTS while the Lenovo has the ...
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1answer
43 views

Dedicated CPU allocation to zone in Solaris 11

I have created a zone called web in Solaris 11. Now I want to allocate one dedicated CPU resource to that zone. But it's throwing an error: "No such entry". I did the following... zonecfg:web> ...
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Can a single core of a cpu process more than one process?

This is the reasoning for my question is what I read in a text book which states: Each CPU (or core) can be working on one process at a time. I'm assuming that this used to be accurate but is no ...
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1answer
47 views

What is the power dissipation of the CPU and how does it work?

I'm looking into TLP and there is this setting that I don't know what does it do: # Set Intel P-state performance: 0..100 (%) # Limit the max/min P-state to control the power dissipation of the CPU. #...